Optimizing cell-size in grid-based DDM

In a large scale distributed simulation with thousands of dynamic objects, efficient communication of data among these objects is an important issue. The broadcasting mechanism specified by the Distributed Interactive Simulation (DIS) standards is not suitable for large scale distributed simulations. In the high level architecture (HLA) paradigm, the Runtime Infrastructure (RTI) provides a set of services, such as data distribution management (DDM) among federates. The goal of the DDM module in RTI is to make the data communication more efficient by sending the data only to those federates that need the data, as opposed to the broadcasting mechanism employed by DIS. Several DDM schemes have appeared in the literature. We discuss grid based DDM and develop a DDM model that uses grids for matching the publishing/subscription regions, and for data filtering. We show that appropriate choice of the grid-cell size is crucial in obtaining good performance. We develop an analytical model and derive a formula for identifying the optimal cell size in grid-based DDM